1. Technical Field
The preset invention relates to a production system having a cooperating process area, by which a robot and a human can simultaneously perform a task in the same area.
2. Description of the Related Art
In the prior art, in a production system using a robot, a safety fence is normally employed in order to completely separate an operation area of the robot from the operation area of a human, whereby the robot and the human cannot simultaneously perform a task in the same area. To ensure safety, the human cannot enter the movement range of the robot when the robot is in operation.
In recent years, it has been desirable that a human can perform a setup task or the like within the movement range of the robot when the robot is in operation, in order to improve productivity or the system. In this connection, in the prior art, a stopper, for limiting motion of each axis of the robot so as to limit the movement range of the robot, is employed, whereby a protection area, which the human can enter without a risk, is obtained within the movement range of the robot.
However, if the stopper is used to limit the movement range of the robot, the protection area which the human can enter must be large, which results in the operation area of the robot being smaller. As a result, the tasks of the robot are limited, and/or the efficiency of the robot may be deteriorated. Further, since it is necessary to remove the stopper to change the protection area, the protection area cannot be changed during the robot is operated, whereby the motion of the robot may be limited even when the task of the human is not necessary. Accordingly, it is difficult to improve the productivity of the system by using the stopper.
When the human enters the movement range of the robot and the robot supplies a workpiece to the human or receives a workpiece from the human, it is necessary that the human and the robot perform such a task in the same area. In such a case, generally, the human must enter the movement range after the motion of the robot is stopped, whereby the productivity of the robot may be deteriorated.
Japanese Unexamined Patent Publication No. 2007-283450 discloses a sensor adapted to detect that a human or a robot enters an operation area where the human may perform a task, the operation area being defined within a movement range of the robot. When the sensor detects entry of the human or robot, the motion of the robot is stopped or decelerated by means of a safety controller or the like, for the safety of the human. Further, in the invention of Japanese Unexamined Patent Publication No. 2007-283450, a plurality of areas, where the human may perform a task, are defined within the movement range of the robot, and then a sensor adapted to detect that the human or the robot enters each area. In this case, the sensor may be activated or deactivated by a switching operation. Due to this, the human and the robot may alternately perform a task in the same area.
In the constitution disclosed in Japanese Unexamined Patent Publication No. 2007-283450, the human and the robot cannot simultaneously perform a task in the same area. In view of cost-consciousness in recent years, it is required that the human and the robot be able to simultaneously perform a task (or cooperative task) in the same area. In other words, in such a cooperative task, the human performs a complicated task such as assembling, and the robot supplies necessary components to the human. In such a case, the production efficiency may be improved by the cooperative task.